Automatic hand gun

ABSTRACT

This invention relates to a recoil-actuated automatic hand gun, which provides for utilizing a maximum sized cartridge in a hand gun system. The reactive thrust as the bullet leaves the muzzle of this gun causes a barrel, barrrel extension, receiver, and bolt to slide back locked together a set distance during initial motion until the bullet leaves the bore of the gun, and the gas pressure decreases to a level low enough to permit the safe unlocking of a locked breech action. The sliding receiver reaches its limit of travel and hits a portion of the frame of the pistol. A through-slot in the bolt bears the cam surfaces which rotate the bolt out of breech-locking splines in the breech action thereby to release the bolt from engagement with the receiver and permit the inertia of the bolt to carry it backwards to perform ejection, cocking, and the loading of a new cartridge. In order to replace some of the dissipated energy and to increase the speed of travel of the bolt to load spring-return mechanisms, and to perform the functions of the bolt with the speed required, a rotary, mechanical accelerator forms a part of the action and imparts a blow to the bolt at the time that the receiver reaches its stop position. The bolt is rotated out of the breech-locked position by balanced cam follower means fixed to the frame that follow the cam surfaces, and upon return to the breech-locked lock position, the entire assembly travels as a unit to the battery position with a loaded cartridge in the chamber. A safety tappet pin engages a spiral groove in the bolt to prevent premature firing before the action has reached an appropriate position. The bolt is adapted with unique ejection means, which ejects the spent cartridge case forward and away from the shooter&#39;&#39;s head and face.

United States Patent Sanford June 17, 1975 AUTOMATIC HAND GUN causes abarrel, barrrel extension, receiver, and bolt to slide back lockedtogether a set distance during initial [75] lnvemor' Harry SaniordArcadia Cahf' motion until the bullet leaves the bore of the gun, and[73] Assigneet El Monte, Califthe gas pressure decreases to a level lowenough to permit the safe unlocking of a locked breech action.

[22] Filed May 1973 The sliding receiver reaches its limit of travel andhits [21] Appl. No.: 360,159 a portion of the frame of the pistol. Athrough-slot in the bolt bears the cam surfaces which rotate the bolt 62D i s i zg g fi 23 Pt N out of breech-locking splines in the breechaction l 1 2:5 3 ay a thereby to release the bolt from engagement withthe receiver and permit the inertia of the bolt to carry it backwards toperform ejection, cocking, and the load- [31 :J.S.:|l. ing of a newcartridge. In order to replace some of the l I72 85 dissipated energyand to increase the speed of travel 1 0 of the bolt to loadspring-return mechanisms, and to perform the functions of the bolt withthe speed re- [56] References Cited quired, a rotary, mechanicalaccelerator forms a part UNITED STATES PATENTS of the action and impartsa blow to the bolt at the time 512,437 H1894 Griffit et a! 39/172 thatthe receiver reaches its stop position. The bolt is 800,l03 9/1905HEllfl'ltZSCh 89/169 rotated out of the breechJocked position balancedFOREIGN PATENTS OR APPUCA'HONS cam follower means fixed to the framethat follow the 133 85 10/1919 United Kingdom 89/, cam surfaces, andupon return to the breech-locked Primary Examiner-Stephen C. BentleyAttorney, Agent, or FirmDonald D. Mon

57 ABSTRACT This invention relates to a recoil-actuated automatic handgun, which provides for utilizing a maximum sized cartridge in a handgun system. The reactive thrust as the bullet leaves the muzzle of thisgun lock position, the entire assembly travels as a unit to the batteryposition with a loaded cartridge in the chamber. A safety tappet pinengages a spiral groove in the bolt to prevent premature firing beforethe action has reached an appropriate position. The bolt is adapted withunique ejection means, which ejects the spent cartridge case forward andaway from the shooters head and face.

4 Claims, 13 Drawing Figures PATENTEIJJUN 17 I975 S'riEET 7n l; C

PATENTEDJUN 17 ms Sl'iEET QQ Q AUTOMATIC HAND GUN This is a division ofapplicants co-pending US. Pat. application Ser. No. 145,259, filed May20, 1971, entitled Automatic Hand Gun," now US. Pat. No. 3,780,618,issued Dec. 25, 1973.

BACKGROUND OF THE INVENTION This invention relates generally to handguns which have recoilactuated mechanisms, for breech-locking withrotational motion, and for loading and cocking.

There have been several attempts to produce a hand gun capable of firinglarge caliber, high power cartridges at high muzzle velocities, but inthe past, all such inventions have failed due to inherent weaknesses inconcept.

A hand gun with rotating breech lock was invented by Andreas WilhelmSchwarzlose, shown in a patent issued in Britain in 1892, Pat. No.23,881, to be followed by Pat. No. 1934 of 1898 in England to the sameinventor. Only the model of 1898 and the rotating breech lock, and inthis model the bolt rotation was accomplished by a single grooveengaging a pin which acted as cam follower to rotate the bolt. The framewas substantially open, and the force applied to the bolt wasunbalanced, thereby creating binding stresses in rotation. To quote thebook on such weapons, called The Hand Gun", by Geoffrey Boothroyd, Aswith most of the selfloading dinosaurs, the Schwarzlose will work quitesatisfactorily when kept clean and lubricated. A very well-made pistol,it is a delight to handle, but the mechanism is too complex, and thereare far too many parts for it to function with any degree of reliabilityunder anything but the most benign conditions."

This quotation reflects the fact that the design did not take intoaccount the dynamics and directions of forces required to rotate andreturn the bolt, and to operate the breech-locking mechanism, as well asfor the timing and positioning of the barrel to insure feeding of thecartridges.

At about this same period there was invented in England the Mars pistolwhich is shown in British Pat. No. 14,777, issued on Aug. 17, 1900. Thisfollowed a previous design granted British Pat. No. 9067 in 1898. Thispistol and its history was completely described in The Gun Digest for1961," published by The Gun Digest Company, Chicago, 111. To quote amilitary report cited in the article, The recoil of these pistols isvery severe. Mr. Fairfax should be asked whether he could alter the.45-inch pistol so as to give a velocity not greater than 1000 f.s., andas much less down to 800 as he could arrange for. In other portions ofthis article, it is pointed out that the certainty of action was notvery good, particularly in the smaller size cartridges. To quote atechnical report included in the article, The pistol has jammed severaltimes, the last time necessitating stripping before it could be madesafe. The cause of this jam was apparently the crimping of thecartridges in the magazine No one who fired once with the pistol wishedto shoot with it again. Several of those who fired are good shots and inthe Excellents Pistol Team."

Thus, it can be seen from past records that attempts to make asemi-automatic hand gun to perform with large caliber, high velocitybullets have been failures, and it is the object of this invention toovercome previous difficulties with a design that provides for apractical firearm that will handle the loads and calibers requiredwithout discomfort to the user. A further object of this invention is toprovide rotary return motion to a rotary-locking breech bolt through theuse of a torsion spring loaded by the initial unlocking action of abreech bolt. A further object of this invention is to provide a hand gunwith a slidable receiver to contain the action for absorbing excessenergy of recoil. Still a further object of the invention is to providesafety means to prevent premature firing of the gun until all parts ofthe action are locked and in their rest position ready for firing. Stillanother object of the invention is to provide for feeding of ammunitioninto the chamber without regard to the position of the chamber withrespect to the magazine during the firing cycle. Still a further objectis to provide for a balanced camming action for rotation of the bolt dueto recoil, and to prevent a binding of action under the stresses andspeed of recoil imparted function. Still another object of the inventionis to provide for mechanical accelerator means to utilize excess recoilenergy of the barrel and receiver assembly to impart an added thrust tothe bolt after disengagement unlocking of the breech-locking means inorder to provide energy for the extraction, cocking and loadingoperations.

SUMMARY OF THE INVENTION In accordance with the teaching of the presentinvention, there is provided a frame for the pistol which issubstantially open, but which is provided with a cylindrical bridgingmember across the rear of the open frame which carries a cross-pin toact as a cam follower for a bolt which is provided with a through-slothaving cam means formed thereupon, to be acted upon by the cross-pin. Asemi-circular, tubular receiver has the gun barrel threadably mounted toit and bears spline-type breech-locking means. A cartridge chamber isformed at the end of the barrel which opens into the receiver. A torsionspring is provided at the end of the bolt opposite the breech-lockingend to be loaded by the unlocking rotation of the bolt occurring underrecoil action in order to store energy for aiding the cross-pin to thethrough-slot cam means to rotate and relock the breech-locking action ofthe bolt. A rotary mechanical accelerator, in the form of a partialdisc, is swivelly mounted to the receiver of the hand gun to provide forstriking of the accelerator by the frame of the gun at the conclusion ofrecoil motion of the receiver-barrel assembly, which causes theaccelerator to strike the bolt at the precise moment that the bolt isrotated out of breech-locking relationship to the receiver in order toimpart an additional rearward thrust on the bolt to aid in loadingcertain return springs, in cocking the hammer, in extracting the spendcartridge and in feeding a new cartridge.

All the above features can be understood by reference to the followingspecification in which a detailed description of the preferredembodiment of the invention appears.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation, partiallyin cutaway crosssection, of the presently preferred embodiment of theinvention;

FIG. 2 is a partial side elevation, partially in cutaway cross-section,of the embodiment of FIG. 1 seen from the opposite side,

FIG. 3 is a cross-section taken on line 33 of FIG.

FIG. 4 is a cross-section taken on line 44 of FIG.

FIG. 5 is a cross-section taken on line 55 of FIG.

FIG. 6 is a cross-section taken on line 6-6 of FIGS. a and 10b;

FIG. 7 is a fragmentary cross-section of the side elevation of FIG. 4taken at line 7-7 therein, showing details of constructions;

FIG. 8 is a cross-section taken on line 88 of FIG.

FIG. 9 is a side elevation, partially in cutaway cross section, to showadditional details of construction of FIG. 1;

FIGS. 10a and 10b are exploded views of the embodiment of FIG. 1,showing the details of the component parts. These FIGS. match as anoverlay at the lower right-hand corner of FIG. 10a and the upperleft-hand corner of FIG. 1017.

FIG. 11 is a fragmentary side elevation of the embodiment of FIG. 1; and

FIG. 12 is an end view, partially in cross-section, taken on line l2l2of FIGS. 10a and 10b.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in FIG. 1, theinvention comprises a pistol having a barrel threadably engaged bythreads 21 to a tubular barrel extension-receiver 22. The receiver 22.The receiver 22 has an external extraction port 23 which leads to aninternal cylindrical bore 24. This bore 24 has an opening 26 to theframe 25 of the pistol. This opening 26 can be seen on the explodedviews of FIGS. 8, 10a and 10b. A series of locking splines 27 is formedin the receiver 22 adjacent the barrel 20. There is an undercut 28between the screw threads 21 and the locking splines 27 which permitsturning and locking of the bolt 30 after the external splines 29 havepassed axially through splines 28 into the recess. When so rotated, thesplines bear against one another to lock the slot in a breech-lockingaction. This is best shown in FIGS. 8, 10a and 10b. A pair of slideways31 and 32 engage slots 34 and 33 to slidably mount the barrelreceiverassembly to the frame 25. A rotatable locking key 35 (FIG. 2) engages aslot 36 in the receiver 22 to prevent the receiver 22 from sliding outof assembly with the frame 25 when the bolt breech-locking means isdisengaged. The locking key 35 is rotated out of engagement fordisassembly by lever 37 as may be seen in phantom line in FIG. 2. Amechanical rotary accelerator 38 (FIGS. 4 and 8) is rotatably mounted tothe receiver 22 by the accelerator plate 39. Plate 39 is sometimesreferred to as a block member", and accelerator 38 is sometimes referredto as a rotary accelerator means. One end 40 of the accelerator 38contacts the bolt 30, while the other end of the accelerator has aprotrusion 41 which is adapted to strike a portion of the frame 25 atsurface 42. Accelerator plate 39 is mounted to receiver 22 by pin 63 asshown in FIGS. 8, 10a and 10b, and is wholly contained within thereceiver 22, along the accelerator 38 as can be seen in FIGS, 7 and 8.

The accelerator plate 39 is pinned to the receiver 22, by pin 63 so thatthe flat surface 120, as shown in FIG. 7 abuts surface 121 of receiver22. The arcuate surface 123a of accelerator plate 39 matches the arcuatesurface 123 of the accelerator 38. This surface-tosurface contactprovides bearing action for rotary transmission of the acceleratingforce from the motion of the receiver 22 to the bolt 30 and alsoprovides surface-tosurface transmission of reactive force from theaccelerator 38 through the accelerator plate 39 to the receiver 22.

End 40 and protrusion 41 are sometimes referred to as striking faces,and they are located adjacent to the periphery of the accelerator means,spaced apart on opposite sides of its center of rotation. Theaccelerator is in the form of a segment of a disc (when viewed from theside). The accelerator is joggled, as can be seen in FIG. 8.

The bolt 30, as can be seen in FIGS. 10a and 10b, has a through-slot 43which has formed on its opposing faces cam surfaces 44 and dwellportions 45 and 46. The bolt 30 has a longitudinal passage 47 whichslidably mounts a firing pin 48. One end of the passage 47 is enlargedto form an enlarged bore 51 to accept a helical torsion spring 49. Thetorsion spring 49 has tangs bent radially toward the center at each end,as exemplified by tang 50, and one tang 50 engages a recess in theenlarged bore 51, while the opposite tang 50a engages a recess in thecocking piece 52 (FIG. 10b). The torsion spring is thereby reactedagainst the bolt and against the frame (the cocking piece being mountedto the frame). The cocking piece 52 is adapted with lug slots 54 tomatch mounting lugs 53 on the bolt 30 and so may be removably mounted tothe bolt 30. The bolt lugs 53 pass through the lug slots 54 as thecocking piece 52 is rotated from its vertical position, and there is aclearance groove 110 behind the lug slots 54 which permits the cockingpiece to be rotated to its vertical position, thus locking the cockingpiece to the bolt, but yet permitting the necessary rotation of the bolt30. This may be seen in FIG. 9 most clearly.

In FIGS. 10a and 10b, the through-slot 43, with camming surfaces 44 torotate the bolt 30 in conjunction with cam-follower pin 117, is shown.Dwell surfaces 45 and 46 permit longitudinal motion of the bolt 30without rotation during motion with the breech locked to hold it to thereceiver and also without rotation by itself after having been unlockedby initial rotation.

During the continuing description of this invention, the muzzle end ofthe gun will be defined as the front, the hammer end of the gun as therear, the left side of the gun is that side which is towards the leftwhen the gun is held with the muzzle pointing away from the holder, andthe right side is that side which is toward the right when the gun isheld in the hand with the muzzle pointing away from the holder.

The cocking piece 52 is retained in assembly with the frame by a pair ofspring retainer rods 55 and 56, which are installed within springs 57and 58. Retainer rods 55 and 56 are assembled with springs 57 and 58through enclosed channels 59 and 60, which are disposed at the top ofthe frame 25 and displaced laterally from the centerline on the rightand left sides of the frame 25. The centerline, as referred to in thisand in other parts of the description, is the centerline that passesthrough the bore of the barrel and is common with the bore of thereceiver 22 and the bolt 30. A pair of frame inserts 61 and 62 act asbearing guides for rods 55 and 56, and the rods 55 and 56 are threadablyengaged with the cocking piece 52 and locked in place with nylon threadlocking means.

The trigger 64 is pivotally mounted to the frame by pin 65, which formsof bolt hold-back lever 66. Holdback lever 66 acts in conjunction withsafety lever 67, which has a flat portion 68 that acts as a cam to pushon the surface 69 of holdback lever 66, when the safety lever 67 isdepressed, to raise bolt hold-back lever 66 so that its protrusionfinder 70 engages a face of bolt 30 to hold the bolt 30 open in the rearposition. Lever 66 has a transversely extending portion 71 which has alower surface 72 which is adapted to be engaged by a portion of themagazine follower 73 so that, upon the firing of the last cartridge,lever 66 is pushed upwards so that its protrusion finger 70 will holdthe bolt open, signalling time to remove the empty magazine 74 andreplace with a fresh loaded one. Safety lever 67 is mounted to rotate inthe frame 25 extending from the left through to the right side of theframe and having a protruding cylindrical finger 75 which acts in thecam recess 76 of the trigger safety plate 77 to rotate the triggersafety plate 77 downward on pin 78, permitting trigger bar support pin79 to be lowered, preventing the trigger bar 82 from releasing the sear91, and thus firing the gun. Thus, the safety lever 67 has threepositions; horizontal, or center which is the firing position; down,which is the bolt hold-open position; and up, which is the triggersafety position. All three of these positions being signalled and heldin place by detent 80 and detent spring 81, which are mounted in theframe 25. Trigger bar 82 is pivotally mounted to trigger 64 by pin 83,and pin 83 also mounts the trigger spring 84, which acts to hold thetrigger forward out of firing position. Compression spring 85 acts tosupport trigger bar 82 and return it to pre-firing position upon releaseof the safety.

The hammer 86 is pivotally mounted to the frame 25 by pin 87 and has aspring 88, spring follower 89, and strut 90 to apply firing pressures ina conventional manner to a firing pin 48, previously described. The sear91 holds the trigger at full or halfcock position and is released byaction of the trigger bar 82 to release hammer 86 for firing. A tappetpin 92 acts on surface 93 of the trigger bar 82, the nose 94 of thetappet pin 92 following the surface of bolt 30 until the tappet pin 92reaches a point where the nose 94 enters a spiral groove 112 (FIG. 11)with a deepened recess 111 at the point 93a where the bolt and receiverare locked together and in the forward battery position ready forfiring. At this time the spring 85 acts to push the trigger bar upwardsagainst the tappet pin 92, pushing the nose 94 into the recess 111 andplacing the trigger bar 82 in firing position for releasing the sear 91,as can be seen in FIG. 5. Therefore, the action is saftied until thepistol is in battery position ready for firing. The straight groove 113allows for the tappet pin 92 to remain engaged in safety position duringnon-rotational motion of the bolt 30.

A conical surface 95 (FIG. b) of the frame acts to guide bullets fromthe magazine into the chamber of the receiver 22. The length of thisconical surface 95 allows the bullets to be fed into the chamber at anypoint along the sliding motion of the action of the receiver 22 inconjunction with a similar conical lead surface 1 15 at the adjacentforward end of the receiver adjacent the interior locking splines 116.

The bolt has a unique ejection feature as shown in FIG. 12 in which thebolt 30 has a recessed front face 98 and a spring-loaded ejector pin 99,which is springloaded by spring 100. A pivoted extractor 101 (FIG. 10a)is mounted on the bolt 30, and the extractor 101 has a hook end 102which protrudes into the recess 98 to extract the spent cartridge case.The spent cartridge case is blown back by the force of the firing toforce back the hooked end 102 of extractor 101 against spring pressureof spring 103, which is located in a recess in the bolt 30 tospring-load the pivotally-mounted extractor 101, and when the cartridgecase has forced the hook end 102 back and is seated in the recess 98 ofthe bolt 30, the hook 102 retains the raised edge of the cartridge caseand the bolt, in its backward motion, extracts the cartridge case fromthe chamber, until a point where the extraction port 105 in the receiver22 is passed by the cartridge, and the pressure of ejector pin 99against the end of the cartridge case flings the empty case out of theextraction port 105.

The entire function of the firearm is described as fol lows: ln batteryor rest position, the bolt 30 is breechlocked to the receiver 22 with acartridge in place in the chamber and the hammer 86 cocked. Pulling thetrigger 64 raises the trigger bar 82, actuating the sear 91, whichreleases hammer 86, striking firing pin 48, to discharge the cartridge.The reaction of the discharge of the bullet causes the assembly ofbarrel 20, receiver 22, and bolt 30 to travel backwards as a unit untilthe movement of the receiver 22 is stopped by the frame 25. At thispoint, the rotary accelerator 38 strikes a portion of the frame 25 andimparts a blow to the bolt 30 at the same time that the cam follower pin117 has rotated the bolt 30 on cam surfaces 44 to free the lockingsplines 29. The added energy to the bolt 30, given by the impact ofrotary accelerator 38 drives the bolt backwards until its motion islimited by the cam follower pin 117. In rotating bolt 30 to unlock thesplines 29, torsion spring 49 is pre-loaded and, during recoil of thebarrel 20, receiver 22 and bolt 30 assembly, as well as during theindependent motion of the bolt 30, return springs 57 and 58 arecompressed. As the bolt 30 travels backwards, it extracts the cartridgefrom the chamber and flings it out of the extractor port. During thisbackward motion, the tappet pin 92 presses the trigger bar 82 down,preventing premature firing of the pistol. After reaching the extremebackward position, at which point the pistol is cocked for the nextfiring, the bolt returns and is rotated under the stored energy oftorsion spring 49 into breech-locking relationship with the receiver 22,and the entire assembly of the action returns to battery position underthe urging of compression springs 57 and 58. During its return motion,the bolt 30 pushes a new cartridge into the chamber of receiver 22.

As is all hand guns of this same general configuration, the frame 25includes a grip member and a cartridge clip chamber 131 formed withinthe grip member.

As in all modern pistols, the barrel 20 has an internal, spiral riflingthat imparts a spin to the bullet to provide a straight and true flight,move first, without tumbling end-for-end, or wobbling and losingprecision. For right-hand rifiing, the bullet would spin to the right,and the spinning bullet, as well as expanding gases, would impart areactive left-hand torque to the barrel which the shooter's hand wouldhave to overcome. In the present invention, the rotating bolt imparts areactive torque to the frame 25 of the pistol through the cam pin 117.Therefore, by having a left-hand rotation on the bolt, the reactivetorque on pin 117 would be of righthand, and so would help offset theleft-hand reactive torque of the bullet, thus giving a steadier firingof the firearm and less strain on the shooter. At the conclu sion of itsrearward motion, the receiver 22 is free to travel forward beforeengagement with the returning bolt and, at any point in the returnmotion, it can receive the new bullet. After the last bullet has beenfired, the follower 73 of the magazine 74 pushes up on the bolthold-back bar, holding the bolt open to signal that reloading isnecessary and saving the shooter the trouble of opening the bolt toinsert a new magazine for reloading. The bolt may be held open after theempty magazine is extracted by pushing down on the safety lever 67 tohold-open bar 66 upwards.

This invention is not to be limited by the embodiment shown in thedrawings and described in the description, which is given by way ofexample and not of limitation, but only in accordance with the scope ofthe appended claims.

I claim:

1. In an automatic pistol having a frame and a recoilactuated boltmounted to said frame and rotated by cam means for breech-locking withspline means, and by primary recoil energy imparted to said bolt by therecoil of a barrel and receiver assembly, having a trigger mechanism forfiring, improvements which comprise:

torsion spring means, said torsion-spring means engaging the bolt andthe frame of said pistol and being reacted against each of them, saidtorsionspring means being preloaded by unlocking rotation of said bolt,and said torsionspring means releasing stored energy for rotation ofsaid bolt to breech-lock the same;

mechanical accelerator means, said mechanical accelerator means removingenergy from said barrel and receiver assembly and transferring saidenergy by impact to said bolt, said energy transfer imparting asecondary energy input to said bolt after said breech-locking isreleased, said accelerator means being in the form of a segment of adisc, said disc being mounted for rotation on said movable receiver, apair of striking faces on the accelerator means adjacent the peripherythereof, but spaced apart on opposite sides of the center of rotationthereof, one of said pair of striking faces striking a portion of saidframe of said pistol at the conclusion of motion of said barrel and saidreceiver assembly in one direction, the other face of said pair strikingsaid bolt at the instant of unlocking of said breech lock to impart asecondary energy transmitting impact to said bolt.

2. A recoil-actuated firearm which comprises:

a frame;

a receiver member, said receiver member having a longitudinal bore;

a barrel member, said barrel member being mounted to said receivermember coaxially with said bore, said receiver member being slidablymounted to said frame;

a bolt member, said bolt member being slidably mounted on said framecoaxially within said receiver member;

rotary accelerator means, said rotary accelerator means being mounted tosaid receiver member in energy-transfer relationship therewith, wherebyto transfer energy of recoil from said receiver member to said boltmember by striking said frame member and swiveling to strike said boltmember; and an accelerator block member, said block member mounted tosaid receiver member, said block member having an arcuate surface, saidrotary accelerator means having an arcuate surface, said arcuatesurfaces of said accelerator block member and of said rotary acceleratormeans abutting one another for rotatable mounting said rotaryaccelerator means.

3. Apparatus according to claim 2 in which rotary breech-locking meansis disposed between said bolt member and said receiver member, said boltmember having through-slot means; said through-slot means having opposedcam surface means and cam follower means mounted to said frame memberand engaging said cam surface means.

4. Apparatus according to claim 2 in which rotary spring means ismounted to said bolt member and to said frame, said rotary spring meansbeing pre-loaded by recoil motion of said bolt member to store energyfor return motion actions of said bolt member.

=F t t

1. In an automatic pistol having a frame and a recoil-actuated boltmounted to said frame and rotated by cam means for breechlocking withspline means, and by primary recoil energy imparted to said bolt by therecoil of a barrel and receiver assembly, having a trigger mechanism forfiring, improvements which comprise: torsion spring means, saidtorsion-spring means engaging the bolt and the frame of said pistol andbeing reacted against each of them, said torsion-spring means beingpreloaded by unlocking rotation of said bolt, and said torsion-springmeans releasing stored energy for rotation of said bolt to breechlockthe same; mechanical accelerator means, said mechanical acceleratormeans removing energy from said barrel and receiver assembly andtransferring said energy by impact to said bolt, said energy transferimparting a secondary energy input to said bolt after saidbreech-locking is released, said accelerator means being in the form ofa segment of a disc, said disc being mounted for rotation on saidmovable receiver, a pair of striking faces on the accelerator meansadjacent the periphery thereof, but spaced apart on opposite sides ofthe center of rotation thereof, one of said pair of striking facesstriking a portion of said frame of said pistol at the conclusion ofmotion of said barrel and said receiver assembly in one direction, theother face of said pair striking said bolt at the instant of unlockingof said breech lock to impart a secondary energy transmitting impact tosaid bolt.
 2. A recoil-actuated firearm which comprises: a frame; areceiver member, said receiver member having a longitudinal bore; abarrel member, said barrel member being mounted to said receiver membercoaxially with said bore, said receiver member being slidably mounted tosaid frame; a bolt member, said bolt member being slidably mounted onsaid frame coaxially within said receiver member; rotary acceleratormeans, said rotary accelerator means being mounted to said receivermember in energy-transfer relationship therewith, whereby to transferenergy of recoil from said receiver member to said bolt member bystriking said frame member and swiveling to strike said bolt member; andan accelerator block member, said block member mounted to said receivermember, said block member having an arcuate surface, said rotaryaccelerator means having an arcuate surface, said arcuate surfaces ofsaid accelerator block member and of said rotary accelerator meansabutting one another for rotatable mounting said rotary acceleratormeans.
 3. Apparatus according to claim 2 in which rotary breech-lockingmeans is disposed between said bolt member and said receiver member,said bolt member having through-slot means; said through-slot meanshaving opposed cam surface means and cam follower means mounted to saidframe member and engaging said cam surface means.
 4. Apparatus accordingto claim 2 in which rotary spring means is mounted to said bolt memberand to said frame, said rotary spring means being pre-loaded by recoilmotion of said bolt member to store energy for return motion actions ofsaid bolt member.